DISEASE CHARACTERISTICS: Histologically proven grade IV astrocytoma or glioblastoma multiforme confined to 1 or both hemispheres of the brain Confirmation of histology by NIH neuropathology review required MRI or CT completed within 3 weeks of initial evaluation No clinically apparent leptomeningeal metastases No uncontrolled seizures despite standard anticonvulsant therapy No history of epilepsy diagnosed a year or more before glioblastoma